我正在尝试使用Flutter和Firebase构建我的第一个移动应用程序。当我尝试显示和存储照片时,出现以下问题:
错误:参数类型“Future”无法分配给参数类型“File”。(argument_type_not_assignable at [whereassistant] lib/main.dart:85)
我可能需要进行一些强制转换,但我不知道如何正确地执行它。
这是我的Future文件声明:
Future<File> _imageFile;
我正在拍摄一张照片,该照片会显示在屏幕上:
setState(() {
_imageFile = ImagePicker.pickImage(source: source);
});
但是当我尝试将照片发送到 Firebase 时,出现了错误:
final StorageUploadTask uploadTask = ref.put(_imageFile);
final Uri downloadUrl = (await uploadTask.future).downloadUrl;
这是我正在使用的类,基于一个代码示例:
class _MyHomePageState extends State<MyHomePage> {
Future<File> _imageFile;
void _onImageButtonPressed(ImageSource source) async {
GoogleSignIn _googleSignIn = new GoogleSignIn();
var account = await _googleSignIn.signIn();
final GoogleSignInAuthentication googleAuth = await account.authentication;
final FirebaseUser user = await _auth.signInWithGoogle(
accessToken: googleAuth.accessToken,
idToken: googleAuth.idToken,
);
assert(user.email != null);
assert(user.displayName != null);
assert(!user.isAnonymous);
assert(await user.getIdToken() != null);
final FirebaseUser currentUser = await _auth.currentUser();
assert(user.uid == currentUser.uid);
setState(() {
_imageFile = ImagePicker.pickImage(source: source);
});
var random = new Random().nextInt(10000);
var ref = FirebaseStorage.instance.ref().child('image_$random.jpg');
final StorageUploadTask uploadTask = ref.put(_imageFile);
final Uri downloadUrl = (await uploadTask.future).downloadUrl;
}
@override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: const Text('Where Assistant'),
),
body: new Center(
child: new FutureBuilder<File>(
future: _imageFile,
builder: (BuildContext context, AsyncSnapshot<File> snapshot) {
debugPrint('test recup image');
print(snapshot);
if (snapshot.connectionState == ConnectionState.done &&
snapshot.data != null) {
return new Image.file(snapshot.data);
} else if (snapshot.error != null) {
return const Text('Error picking image.');
} else {
return const Text('No image so far.');
}
},
),
),
floatingActionButton: new Column(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
new FloatingActionButton(
onPressed: () => _onImageButtonPressed(ImageSource.gallery),
tooltip: 'Pick an image from gallery',
child: new Icon(Icons.photo_library),
),
new Padding(
padding: const EdgeInsets.only(top: 16.0),
child: new FloatingActionButton(
onPressed: () => _onImageButtonPressed(ImageSource.camera),
tooltip: 'Take a Photo',
child: new Icon(Icons.camera_alt),
),
),
],
),
);
}
}